AD 1250-1500 Late Byzantium

In AD 1261 the Byzantine emperor, Michael Palaeologus, with Turkish help, recovered Constantinople from the westerners who had occupied it since the Fourth Crusade. The city had, however, been ransacked and the empire was a shadow of its former self, consisting of a Balkan state with a fringe of Asian territory. The Bulgarians were never again to be contained and the great maritime cities of Italy, Venice and Genoa, had taken over the Aegean island area.

To deal with the threat from a Serb prince, 14th-century emperors asked for help from the Osmanli Turks, later known as the Ottomans. The inexorable advance of Ottoman power in Europe brought with it the gradual decline of Byzantium. By 1371 the Ottomans had defeated the Serbs on the River Maritsa, and in 1388 Bulgaria became a tributary state. In 1389 Ottoman victory over allied Christian forces at the battle of Kosovo effectively crushed all military opposition. By 1400 the Ottomans had taken over much of the Balkans, conquering Serbia in 1459. They had defeated another Crusade and subsequently over-run Greece. Throughout the first half of the 15th century Constantinople stood against them, but in 1453 it fell to Sultan Mehmet II (1451-1481) and became part of the Ottoman empire.